Single Femoral Socket Double-Bundle Anterior Cruciate Ligament Reconstruction Using Tibialis Anterior Tendon: Description of a New Technique

The native anterior cruciate ligament (ACL) has been shown to consist of 2 functional bundles with independent behavior throughout range of knee motion. Conventional arthroscopic ACL reconstruction techniques selectively recreate the anteromedial bundle of the native ACL only. Numerous studies have reported the failure to restore normal knee kinematics in an ACL-deficient knee using a single-bundle reconstruction. It has been suggested that by reconstructing both the anteromedial and posterolateral bundles of the ACL, more normal knee kinematics may be achieved. Several authors have described surgical techniques to recreate the 2 functional bundles and they range from using 2 femoral tunnels to using a single femoral tunnel with the other bundle passed over the top. This article describes a new technique of recreating the 2 functional bundles of the ACL with tibialis anterior tendon allograft using a single femoral socket.     

Arthroscopic anatomic double bundle anterior cruciate ligament reconstruction: Our experience with follow-up of 4 years

BackgroundDouble bundle (DB) anterior cruciate ligament (ACL) reconstruction has been proposed to recreate the natural anatomy of ACL. Reconstruction of the anatomy of both the bundles of ACL has been thought to be able to restore the rotational stability of the knee joint. Nevertheless, it remains unclear whether DB reconstruction has better functional outcome than single bundle (SB) ACL reconstruction.PurposeTo evaluate the clinical outcomes, patient satisfaction and manual laxity tests of knee in patients treated with DB ACL reconstruction in Indian population.MethodsWe prospectively followed 25 patients with an isolated ACL injury operated for DB ACL reconstruction after applying the inclusion and exclusion criteria. Patients were evaluated pre-operatively and in the post-operative period at regular intervals with the minimum follow up of 4 years. Clinical stability was assessed by anterior drawer test, Lachman test and pivot shift test. Functional outcome was assessed by IKDC, Lysholm and Modified Cincinnati scores.ResultsAt the end of 4 years, functional outcome in terms of all subjective scores was satisfactory. Graded stability results of the Lachman, Anterior drawer and pivot shift tests were almost near to that in normal knee. No complication occurred post-operatively.ConclusionAnatomical DB ACL reconstruction seems to offer satisfactory results in terms of subjective scores and stability tests to patients with ACL tear. It has been found to be associated with no obvious complications and no failures. However a larger patient pool is desired for conclusive results.     

Trantibial anterior cruciate ligament double bundle reconstruction technique: two tibial bundle in one tibial tunnel

The anterior cruciate ligament (ACL) consists of two functional bundles that behave independently throughout the range of knee motion. Many two-bundle reconstruction techniques have been introduced to restore the function of the two bundles of the ACL. Generally, two femoral and two tibial tunnels are made during the surgery for a two-bundle ACL reconstruction. However, the procedure is technically demanding and time consuming. This paper describes one-tibial-two-femoral ACL double bundle reconstruction technique with a sextuple-stranded hamstring autograft. The anteromedial femoral tunnel is made using transtibial drilling technique and posterolateral femoral tunnel is made using outside-in technique. The two bundles in a single tibial tunnel are separated using biodegradable interference screw. Stable and adequate femoral fixation of the two bundles with a transtibial fixation and bioabsorbable screw can be obtained. This technique is relatively simple, and replicates the anatomy and differential behavior of the two native bundles of ACL more effectively.     

Partial Rupture of the Anterior Cruciate Ligament

The anterior cruciate ligament (ACL) consists of two major fiber bundles, namely the anteromedial (AM) and posterolateral (PL) bundles. Although disagreement exists among arthroscopic surgeons about the occurrence of isolated ruptures of the AM or PL bundle, there are reports of partial ruptures of the ACL in the literature. A potential reason for controversy could be that with conventional magnetic resonance imaging, isolated PL ruptures are difficult to diagnose because of the oblique course of this bundle. Another reason could be that isolated ruptures of the AM or PL bundle are difficult to diagnose during arthroscopy. During arthroscopy, an isolated PL bundle rupture can easily be missed when viewing from the standard anterolateral portal. The AM bundle overlies the PL bundle, and the PL bundle can only be seen by retraction of the AM bundle with a probe. When the knee is extended, the PL bundle is tight and the AM bundle is moderately lax. As the knee is flexed, the femoral attachment of the ACL becomes horizontally oriented, causing the AM bundle to tighten and the PL bundle to relax. Whereas the AM bundle is the primary restraint against anterior tibial translation in flexion, the PL bundle tends to stabilize the knee near full extension, particularly against rotatory loads. The different bundle contributions to knee stability in the flexed or extended positions can aid in the diagnosis of partial ACL ruptures. Isolated rupture of the AM bundle has more effect on the anterior drawer sign than on the Lachman test, whereas the converse is true for isolated rupture of the PL bundle. Rotational instability as a result of PL bundle rupture can be tested with the pivot-shift test. Pivot shift can be negative in cases with isolated AM bundle rupture. If only one bundle of the ACL is torn, isolated AM or PL bundle reconstruction should be considered. Although potentially difficult, a careful diagnostic evaluation is necessary before ACL surgery.     

Functional outcome of double-bundle anterior cruciate ligament reconstruction

Background/PurposeThe anterior cruciate ligament (ACL) is one of the most frequently injured ligaments in the knee joint and is generally treated by surgical reconstruction. A possible reason for the unsatisfactory nature of this reconstruction is that the complex function of the ACL is not reproduced by the traditional ACL reconstruction procedure, which replicates only a single bundle rather than the two separate bundles that form the original ACL. It has been suggested that re-establishment of the double-bundle anatomy of the ACL is crucial for obtaining a better restoration of the normal biomechanics of the knee and improving the knee's rotatory stability. The purpose of this study was to evaluate the authors' current double-bundle ACL reconstruction technique and assess the various functions of the anteromedial and posterolateral bundles.MethodsPatients were assessed for instability and laxity after a mean follow-up of 16 months (range, 12–26 months). The range of motion was measured and compared with the opposite normal knee. Clinical evaluation was performed using the modified Lysholm scoring scale, the Tegner activity scale, and the International Knee Documentation Committee (IKDC) rating system.ResultsThe study included 20 patients, 15 males and five females, with a mean age of 22.7 years (range, 18–29 years) at the time of surgery. Following the procedure described by Yasuda et al, double-bundle ACL reconstruction, which anatomically reproduces the anteromedial and posterolateral bundles using hamstring tendon grafts, was performed on patients under general anesthesia. The clinical results for the Lysholm rating system were good to excellent, being 71 points preoperatively and 94 postoperatively. The IKDC rating was 65% preoperatively and 92% postoperatively. All patients showed a negative pivot shifting test.ConclusionThe ACL not only is the primary restraint on anterior tibial translation but also contributes considerably to normal knee kinematics. Our study showed that the four-tunnel double-bundle ACL reconstruction provides significant advantages in terms of anterior and rotational stability as well as objective IKDC. The subjective measurement of postoperative functional results using either the Lysholm or the IKDC rating system revealed a promising outcome after a short follow-up period.     

In vivo anterior cruciate ligament elongation in response to axial tibial loads

Background  The knowledge of in vivo anterior cruciate ligament (ACL) deformation is fundamental for understanding ACL injury mechanisms and for improving surgical reconstruction of the injured ACL. This study investigated the relative elongation of the ACL when the knee is subject to no load (<10 N) and then to full body weight (axial tibial load) at various flexion angles using a combined dual fluoroscopic and magnetic resonance imaging (MRI) technique. Methods  Nine healthy subjects were scanned with MRI and imaged when one knee was subject to no load and then to full body weight using a dual fluoroscopic system (0°–45° flexion angles). The ACL was analyzed using three models: a single central bundle; an anteromedial and posterolateral (double functional) bundle; and multiple (eight) surface fiber bundles. Results  The anteromedial bundle had a peak relative elongation of 4.4% ± 3.4% at 30° and that of the posterolateral bundle was 5.9% ± 3.4% at 15°. The ACL surface fiber bundles at the posterior portion of the ACL were shorter in length than those at the anterior portion. However, the peak relative elongation of one posterolateral fiber bundle reached more than 13% whereas one anteromedial fiber bundle reached a peak relative elongation of only about 3% at 30° of flexion by increasing the axial tibial load from no load to full body weight. Conclusions  The data quantitatively demonstrated that under external loading the ACL experiences nonhomogeneous elongation, with the posterior fiber bundles stretching more than the anterior fiber bundles.     

A prospective randomised study of anatomical single-bundle versus double-bundle anterior cruciate ligament reconstruction: quantitative evaluation using an electromagnetic measurement system

We conducted a prospective randomised study of anatomical single-bundle (A-SB group) versus double-bundle (A-DB group) anterior cruciate ligament (ACL) reconstruction using the hamstrings tendons. Twenty patients with unilateral ACL deficiency were randomised into two groups. We created the bone tunnels at the position of the original insertion of the anteromedial bundle footprint and posterolateral bundle footprint in the A-DB group and at the central position between these two bundles in the A-SB group. All of the patients were tested before ACL reconstruction and one year after surgery. The KT-1000 measurements, isokinetic muscle peak torque and heel-height difference were evaluated and the general knee condition was assessed by Lysholm score. For pre- and postoperative stability assessment, we used the six-degrees-of-freedom of knee kinematic measurement system using an electromagnetic device (the EMS) for quantitative assessment during the Lachman test and the pivot shift test. There were no significant differences in the KT-1000 measurements, isokinetic muscle peak torque, heel-height difference, and Lysholm score at one-year follow-up between these two groups. The EMS data showed there were significant differences in the acceleration of the pivot shift test between the operated knee and the contralateral normal knees in the A-SB group. In conclusion, clinical outcomes were equally good in both groups. However, the EMS data showed the anatomical double-bundle ACL reconstruction tended to be biomechanically superior to the single-bundle reconstruction.     

Distribution of in situ forces in the anterior cruciate ligament in response to rotatory loads.

The anterior cruciate ligament (ACL) can be anatomically divided into anteromedial (AM) and posterolateral (PL) bundles. Current ACL reconstruction techniques focus primarily on reproducing the AM bundle, but are insufficient in response to rotatory loads. The objective of this study was to determine the distribution of in situ force between the two bundles when the knee is subjected to anterior tibial and rotatory loads. Ten cadaveric knees (50+/-10 years) were tested using a robotic/universal force-moment sensor (UFS) testing system. Two external loading conditions were applied: a 134 N anterior tibial load at full knee extension and 15 degrees, 30 degrees, 60 degrees, and 90 degrees of flexion and a combined rotatory load of 10 Nm valgus and 5 Nm internal tibial torque at 15 degrees and 30 degrees of flexion. The resulting 6 degrees of freedom kinematics of the knee and the in situ forces in the ACL and its two bundles were determined. Under an anterior tibial load, the in situ force in the PL bundle was the highest at full extension (67+/-30 N) and decreased with increasing flexion. The in situ force in the AM bundle was lower than in the PL bundle at full extension, but increased with increasing flexion, reaching a maximum (90+/-17 N) at 60 degrees of flexion and then decreasing at 90 degrees. Under a combined rotatory load, the in situ force of the PL bundle was higher at 15 degrees (21+/-11 N) and lower at 30 degrees of flexion (14+/-6 N). The in situ force in the AM bundle was similar at 15 degrees and 30 degrees of knee flexion (30+/-15 vs. 35+/-16 N, respectively). Comparing these two external loading conditions demonstrated the importance of the PL bundle, especially when the knee is near full extension. These findings provide a better understanding of the function of the two bundles of the ACL and could serve as a basis for future considerations of surgical reconstruction in the replacement of the ACL.     

Assessment and Augmentation of Symptomatic Anteromedial or Posterolateral Bundle Tears of the Anterior Cruciate Ligament

The anterior cruciate ligament (ACL) consists of 2 anatomic and functional bundles, the anteromedial (AM) and posterolateral (PL) bundle. Depending on the mechanism of injury, there are different injury patterns to the AM and PL bundles, demonstrating a wide spectrum of partial ACL tears. Clinical interest has recently focused on establishing pre- and intraoperative ways of assessing the different types of symptomatic partial ACL injuries in order to perform an individual ACL augmentation according to the specific injury pattern. Theoretically, sparing the intact parts of the ACL may increase vascularization and proprioception, may optimize the accuracy of the ACL reconstruction, and may result in better stability and improved clinical outcome for the patient. However, an isolated reconstruction of the AM or PL bundle is an advanced arthroscopic procedure that requires a precise pre- and intraoperative diagnostic assessment of the injury pattern, an exact arthroscopic knowledge of the anatomic insertion sites, a careful debridement, and bone tunnel placement while preserving the intact parts of the ACL. This article will present the concept of partial ACL tears and will describe the clinical, radiologic, and arthroscopic assessment and the arthroscopic technique of isolated AM or PL bundle augmentation.     

Anatomical versus Non-Anatomical Single Bundle Anterior Cruciate Ligament Reconstruction: A Cadaveric Study of Comparison of Knee Stability

Background

The purpose of this study was to compare the initial stability of anatomical and non-anatomical single bundle anterior cruciate ligament (ACL) reconstruction and to determine which would better restore intact knee kinematics. Our hypothesis was that the initial stability of anatomical single bundle ACL reconstruction would be superior to that of non-anatomical single bundle ACL reconstruction.

Methods

Anterior tibial translation (ATT) and internal rotation of the tibia were measured with a computer navigation system in seven pairs of fresh-frozen cadaveric knees under two testing conditions (manual maximum anterior force, and a manual maximum anterior force combined with an internal rotational force). Tests were performed at 0, 30, 60, and 90 degrees of flexion with the ACL intact, the ACL transected, and after reconstruction of one side of a pair with either anatomical or non-anatomical single bundle ACL reconstruction.

Results

Under manual maximal anterior force, both reconstruction techniques showed no significant difference of ATT when compared to ACL intact knee state at 30° of knee flexion (p > 0.05). Under the combined anterior and internal rotatory force, non-anatomical single-bundle ACL reconstruction showed significant difference of ATT compared to those in ACL intact group (p < 0.05). In contrast, central anatomical single bundle ACL reconstruction showed no significant difference of ATT compared to those in ACL intact group (p > 0.05). Internal rotation of the tibia showed no significant difference in the ACL intact, the ACL transected, non-anatomical reconstructed and anatomical reconstructed knees.

Conclusions

Anatomical single bundle ACL reconstruction restored the initial stability closer to the native ACL under combined anterior and internal rotational forces when compared to non-anatomical ACL single bundle reconstruction.     

膝关节前交叉韧带胫骨止点的软组织解剖标记

背景：膝关节前交叉韧带（ACL）重建时,胫骨骨道定位不准会产生重建韧带与髁间窝的撞击或起不到维持膝关节稳定性的作用。因此,确定ACL胫骨止点的位置非常重要。目的：研究膝关节ACL胫骨止点前内束（AMB）和后外束（PLB）与软组织标记后交叉韧带（PCL）和外侧半月板前角的距离,从而明确ACL胫骨止点在胫骨平台的位置,为ACL损伤双束重建提供理论支持。方法：解剖18个膝关节尸体标本（左膝10个,右膝8个）,测量ACL中点、AMB中点、PLB中点与PCL和外侧半月板前角的距离,并分析左、右膝关节是否存在差异。结果：AMB中点与PCL和外侧半月板前角的距离分别为（15.00±3.97）mm和（19.78±4.10）mm;PLB中点与两者的距离分别为（10.17±5.56）mm和（19.50±4.40）mm;ACL中点与两者的距离分别为（12.67±4.52）mm和（19.61±3.87）mm。左右膝关节ACL中点、AMB中点、PLB中点与软组织解剖标记的距离无明显统计学差异。结论：膝关节ACL损伤行手术重建时,可采用PCL和外侧半月板前角作为定位标记。     

Double-bundle Anterior Cruciate Ligament reconstruction: a review of literature

Purpose

Anterior cruciate ligament (ACL) reconstruction has been under intensive discussion and debate, although the anatomy of this ligament was resolved thoroughly almost 200 years ago. The ACL consist of two bundles, anteromedial (AM) and posterolateral (PL). The conventional single-bundle method reconstructs the AM bundle only, while the modern double-bundle technique recreates both bundles for their anatomical sites.

Methods

An English language literature search was undertaken over the years 2000–2012 for ACL reconstruction, double-bundle versus single bundle technique. The search found 14 RCTs and two meta-analyses published to date.

Results

Two of the 14 studies (14 %) showed no difference between the two reconstruction methods while the remaining majority (12 trials, 86 %) concluded that the DB technique was better than the SB method. After the DB reconstruction, rotational stability of the knee was better in seven studies (50 %) and anteroposterior stability in six (43 %). No study spoke for the single-bundle technique. In addition, with the double-bundle technique knee scores were reported to be better in five (36 %) studies, and three trials (21 %) revealed less reoperations in the double-bundle group.

Conclusions

The double-bundle ACL reconstruction technique was reported to have better or at least the same results as the conventional single-bundle method—even at a five-year follow-up. However, the majority of these studies had a rather short follow-up, and thus, longer studies are needed to confirm the true long-term results of ACL surgery. Long follow-up periods are also needed to find out whether double-bundle ACL reconstruction can eventually prevent knee osteoarthritis.     

前十字韧带股骨直接纤维止点重建的力学特征及近期临床疗效

目的探讨前十字韧带(anterior cruciate ligament,ACL)股骨直接纤维止点重建的有限元特征及近期疗效。方法2016年6月至2017年6月接受ACL股骨直接纤维止点双束重建的患者26例,男15例,女11例;年龄(30.5±4.6)岁(范围18~50岁)。所有患者均由同一医生完成自体腘绳肌腱股骨直接纤维止点双束ACL重建手术。通过术后有限元分析、术中Pivot shift试验及Lachman试验、手术前后国际膝关节文献委员会(International Knee Document Committee,IKDC)评分、Lyshlom评分、KT-2000侧侧差值、术后膝关节CT三维重建、膝关节MRI评估膝关节的稳定性、移植物的状态及临床疗效。结果有限元分析中髌骨应力集中在髌尖区域,健侧最大值为(1.62±0.07)MPa、患侧最大值为(1.64±0.02)MPa,差异无统计学意义(t=-1.22,P=1.22);股骨滑车区域应力集中在上极,健侧最大值为(0.73±0.15)MPa、患侧最大值为(0.72±0.14)MPa,差异无统计学意义(t=0.09,P=0.93)。重建后即刻Pivot shift试验均转为阴性,Lachman试验1例Ⅰ度阳性、其余均为阴性。术后CT三维重建示股骨隧道位于ACL股骨止点直接纤维足印区,术后2年MRI矢状面抑脂像示ACL双束呈均匀低信号、连续性及走行良好。Lysholm评分由术前(56.5±3.6)分增加至术后3个月的(61.9±3.2)分、术后2年的(88.5±2.0)分,差异有统计学意义(F=824.72,P<0.001);IKDC评分由术前(48.3±2.8)分增加至术后3个月的(58.0±2.0)分、术后2年的(92.5±2.6)分,差异有统计学意义(F=2256.66,P<0.001);KT-2000侧侧差值由术前(5.6±0.7)mm降低至术后3个月的(1.6±0.5)mm、术后2年的(1.5±0.6)mm,差异有统计学意义(F=389.14,P<0.001)。结论ACL股骨直接纤维止点双束重建能有效恢复膝关节的稳定性及力学环境,具有较好的近期临床疗效。     

Prospective clinical comparisons of semitendinosus versus semitendinosus and gracilis tendon autografts for anatomic double-bundle anterior cruciate ligament reconstruction

Background

The data available from the previously reported clinical studies remains insufficient concerning the hamstring graft preparation in double-bundle anterior cruciate ligament (ACL) reconstruction.

Objective

To test the hypothesis that there are no significant differences between the semitendinosus tendon alone and the semitendinosus and gracilis tendon graft fashioning techniques concerning knee stability and clinical outcome after anatomic double-bundle ACL reconstruction.

Methods

A prospective study was performed on 120 patients who underwent anatomic double-bundle ACL reconstruction according to the graft fashioning technique. The authors developed the protocol to use hamstring tendon autografts. When the harvested doubled semitendinosus tendon is thicker than 6 mm, each half of the semitendinosus tendon is doubled and used for the anteromedial (AM) and posterolateral (PL) bundle grafts (Group I). On the other hand, when the harvested semitendinosus tendon is under 6 mm in thickness, the gracilis tendon is harvested additionally. The distal half of the semitendinosus and gracilis tendons are doubled and used for the AM bundle graft, and the remaining proximal half of the semitendinosus tendon is doubled and used for the PL bundle grafts (Group II). Sixty-one patients were included in Group I, and 59 patients in Group II. The two groups were compared concerning knee stability and clinical outcome 2 years after surgery.

Results

The postoperative side-to-side anterior laxity averaged 1.3 mm in both groups, showing no statistical difference. There were also no significant differences between the two groups concerning the peak isokinetic torque of the quadriceps and the hamstrings, the Lysholm knee score, and the International Knee Documentation Committee evaluation.

Conclusion

There were no significant differences between the two graft fashioning techniques after anatomic double-bundle ACL reconstruction concerning knee stability and postoperative outcome. The present study provided orthopedic surgeons with important information on double-bundle ACL reconstruction with hamstring tendons.

Level of evidence

Level II; prospective comparative study.     

双束重建前十字韧带骨道位置的临床研究

目的 研究双束重建前十字韧带患者术后骨道位置与临床效果的关系,初步探讨双束重建前十字韧带的定位评价.方法 随访研究2005年5至12月33例自体胭绳肌腱双束重建前十字韧带的患者,通过X线片测量其骨道位置.术后29例获14～22个月(平均18个月)随访,进行膝关节功能评分、KT-2000及Biodex肌力测试评价.结果 患者术后IKDC、Lysholm和Tegner评分及KT-2000结果均较术前显著改善(P＜0.01).前内束股骨骨道位于Blumensaat线水平的股骨外髁长度的29.68%±5.25%,高度的16.93%±5.73%.后外束股骨骨道位于Blumensaat线水平的股骨外髁长度的30.33%±9.44%,高度的31.24%±6.87%.前内束和后外束胫骨骨道分别位于胫骨平台长度的32.92%±5.37%和46.33%±7.74%.前内束股骨骨道前后位置与KT-2000 30°前后稳定性呈负相关(P＜0.05),即前内骨道越偏后30°稳定性越好.前内束股骨骨道相对外髁高低程度与患肢术后120°角速度下屈肌力矩呈正相关.后外束股骨骨道前后位置与60°角速度下屈肌力矩呈正相关,后外束胫骨骨道前后位置与120°角速度下屈肌力矩呈负相关.骨道位置与各功能评分均未表现出相关性.结论 双束重建前十字韧带可取得很好的临床效果.X线测量可以较客观、准确地反映骨道的定位情况并分析临床效果.     

关节镜下单束重建治疗前交叉韧带部分断裂的临床研究

目的探讨关节镜下单束重建治疗前叉韧带部分断裂的临床疗效及手术方法。方法回顾性分析2007年6月至2009年10月关节镜下应用单束重建治疗前叉韧带部分断裂12例患者的资料。12例患者中,男9例,女3例,平均年龄37岁。根据IKDC、Lysholm膝关节功能评分进行功能恢复评估。结果 12例患者平均随访13个月,所有患者术后均无感染。术后最后一次随访时Lachman试验（﹢）、前抽屉实验（-）2例,其他患者前抽屉试验、Lachman试验均为阴性。11例膝关节屈伸活动度正常,1例膝关节伸直缺失10°,IKDC评级：11例正常,1例接近正常。术前IKDC主观评分（48.33±12.77）,Lysholm膝关节功能评分（55.42±15.01）;术后末次随访IKDC主观评分（91.42±4.94）,Lysholm膝关节功能评分（95.33±6.02）,差异有统计学意义（P〈0.01）。结论关节镜下单束单隧道重建治疗前叉韧带部分断裂的短期临床疗效满意,保留残存纤维束重建虽然有一定难度,但手术在熟练的关节镜技术下可以顺利施行。     

Review of evolution of tunnel position in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) rupture is one of the commonest knee sport injuries. The annual incidence of the ACL injury is between 100000-200000 in the United States. Worldwide around 400000 ACL reconstructions are performed in a year. The goal of ACL reconstruction is to restore the normal knee anatomy and kinesiology. The tibial and femoral tunnel placements are of primordial importance in achieving this outcome. Other factors that influence successful reconstruction are types of grafts, surgical techniques and rehabilitation programmes. A comprehensive understanding of ACL anatomy has led to the development of newer techniques supplemented by more robust biological and mechanical concepts. In this review we are mainly focussing on the evolution of tunnel placement in ACL reconstruction, focusing on three main categories, i.e., anatomical, biological and clinical outcomes. The importance of tunnel placement in the success of ACL reconstruction is well researched. Definite clinical and functional data is lacking to establish the superiority of the single or double bundle reconstruction technique. While there is a trend towards the use of anteromedial portals for femoral tunnel placement, their clinical superiority over trans-tibial tunnels is yet to be established.     

Teaching of anterior cruciate ligament function in osteopathic medical education

The anterior cruciate ligament (ACL) of the knee and the function of its anteromedial (AM) and posterolateral (PL) bundles are a focus of orthopedic research. Because of the probability that third-year and fourth-year osteopathic medical students will encounter ACL injuries during clinical rotations, it is of paramount importance that students fully understand the functions of the AM and PL bundles as 2 distinct functional components of the ACL. The authors assess the degree to which the AM and PL bundles are discussed within basic science curricula at colleges of osteopathic medicine (COMs). In September 2008, a 6-question survey addressing various aspects of ACL education was mailed to instructors of lower-extremity anatomy at all 28 COMs that existed at that time. Nine of the 21 responding institutions (42.9%) indicated that both the AM and PL bundles of the ACL are discussed within their basic science curricula. Four of these 9 COMs indicated that their instruction mentions that the bundles are parallel in extension and crossed in flexion. Nine of the 21 responding COMs (42.9%) indicated that they instruct students that the AM bundle is a major anterior-posterior restrictor, and 12 (57.1%) indicated that they instruct students that the PL bundle is the major rotational stabilizer of the ACL. In 7 of the 21 responding COMs (33.3%), the AM and PL bundles are identified via direct visualization during anatomic dissection of the ACL. The authors conclude that their findings suggest the need for enhanced presentation of the AM and PL bundles within the basic science curricula at COMs to provide osteopathic medical students with a more comprehensive education in anatomy.